This invention relates to a method of manufacturing rims, e.g. for automobiles or motorcycles, by using fiber-reinforced plastic (hereinafter referred to as "FRP", when applicable) which is light and durable. FRP which is provided according to a method in which reinforced fibers such as carbon fibers, glass fibers or Kevlar (a trade mark of DuPont Co.) fibers are impregnated with thermosetting resin such as epoxy resin or polyester resin, is high in strength and elasticity, resistive against acid and alkali, has a high fatigue limit, is lightweight and is excellent in vibration damping characteristics. Thus, such a FRP is being increasingly employed in various applications as a light structural material. In the future, such a FRP may be more extensively applied to automobiles in order to reduce the weight of the automobiles to thereby increase the fuel economy of the automobiles.